Generally, a sound sleep in a relaxed state affects human health, and therefore a proper use of a pillow for sleep and a function thereof regulates body's metabolism and affects a human body.
The reason why a sleeper feels comfortable only when he/she sleeps on a pillow with a certain height for a sound sleep is that a cervical vertebra supporting a head is not located on the same straight line as a spine but is formed to have a certain curved line, and therefore when a sleeper sleeps on a pillow with a height approximating a deviation in height between the cervical vertebra and the spine of the human body, the sleeper may be seated on the pillow without being sagged thanks to the pillow.
When the height of the pillow is high or low, the cervical vertebra is instantly hardened in a state in which it is spread straight or excessively bowed. In this case, the problem that nerves or muscles around the cervical vertebra are stimulated while the cervical vertebra returns to its shape when he/she stands up and thus a user feels heavy, and in severe cases, the spine is twisted may occur.
As a result, a functional pillow protecting the cervical vertebra has been used in recent. The functional pillow is configured to include a main body made of at least any one of materials such as memory foam, sponge, cotton, and latex and having a flat bottom surface, a cervical vertebra support formed to protrude at a middle part of an upper surface of the main body and supporting a neck to bend a user's head back, an occipital support extended to a back of the cervical vertebra support to be integrally formed with the cervical vertebra support and supporting a user' s head occipital region, a shoulder support extended to a front of the occipital support to be integrally formed with the occipital support and downwardly inclined to support a user's shoulder region, and an air-permeable cover enclosing and supporting an outside of the main body and applying any one of anion, a far infrared ray radiating material, and an aromatic to an inside thereof in a powder or phlegmatic temperament form.
There is a problem in that the pillow is manufactured by compression-molding expensive materials such as urethane and latex, and therefore is very difficult to manufacture, an upper end part of the pillow is provided with a bone conduction speaker, and therefore a headache phenomenon occurs when the pillow is used for a long time, and a user's head deviates from the pillow when the head moves left and right, and therefore the user does not get a pleasant sound sleep.